Processing of regenerated cellulose tubing



May 27, 1958 E. l. LlCHTBLAU PROCESSING OF REGENERATED CELLULOSE TUBING Filed March 30, 1956 jf'ig.Z

INVENTOR ELLIS IRVING LICHTBLAU ATTORNEY United States Patent 6 PROCESSING OF REGENERATED CELLULOSE TUBING Ellis Irving Lichthlau, Kenmore, N. Y., assignor to E. L du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Application March 30, 1956, Serial No. 575,128

4 Claims. (Cl. 154-116) This invention relates to the processing of gel regenerated cellulose tubing. More particularly it relates to connecting ends of seamless gel regenerated cellulose tubing during the printing operation.

Gel regenerated cellulose, after being extruded through an annular orifice to form tubing, is washed, then wound in flattened form as a roll on a core. In a separate operation, the gel regenerated cellulose tubing is printed with the familiar phrases that identify the contents of whisky bottles and similar containers. The tubing is later cut to proper lengths for fitting around the necks of the bottles.

Printing involves first unwinding the flattened tubing from the roll; passing the tubing through a bath containing napthol or the like to make it receptive to the printing dye; passing the tubing through printing rolls, then through washing baths and finally rewinding the printed tubing on wind-up rolls. During the operation it is often necessary to connect two ends of the tubing. Breaks in the tubing inevitably occur and must be repaired and, obviously, tail ends of unwound rolls must be connected to lead ends of new rolls. Heretofore, mends, the term used in this art for these connections, were made by butting the two ends to be connected and sewing them onto a piece of paper or cloth. These mends were in general unsatisfactory. Gel regenerated cellulose being quite limp and pliable is not very receptive to sewing. Any substantial tension separated the mends. Thus, printing speeds, which directly affect tension, were limited. The time consumed in making mends also was significant.

The object of this invention is a method for mending gel regenerated cellulose tubing that is rapid, efiicient, and provides mends that will withstand relatively high tensions. Since the time of mending and the mend strength are limiting factors in determining the rate of printing, another object is to provide a printing process for gel regenerated cellulose tubing that is continuous and which operates at high speeds. Other objects will appear hereinafter.

The objects are accomplished by thoroughly wetting one end of gel regenerated cellulose tubing with an aqueous liquid, and placing it around another end of gel regenerated cellulose tubing for a distance of at least about inches to provide a connection of high strength.

As applied to the process of printing gel regenerated cellulose tubing, the invention comprises unwinding gel regenerated cellulose tubing into a liquid bath in which the tubing is lagged free of tension; thoroughly wetting one end with an aqueous liquid; mending the tubing by inserting the other end into said wetted end of the tubing for a distance of at least about 10 inches; drawing the mended tubing from the lag bath through a printing press; printing said tubing; and thereafter washing and collecting the printed tubing.

The details and advantages of the invention will be apparent from the following description when read in conjunction with the accompanying illustrations in which:

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Figure 1 is a schematic flow sheet of the process showing the important pieces of equipment.

Figure 2 is a plan view of a vacuum finger useful in the present invention.

Figure 3 is a sectional view taken along 33 of Figure 2.

As used in this specification, the lead end refers to the end of the regenerated cellulose tubing that is integral with the tubing which has not undergone any printing; the tail end refers to the end that is integral with the tubing that has undergone some printing.

In a specific embodiment of the invention, gel regenerated cellulose tubing was unwound from roll, 11, through a pair of nip rolls, 12, driven by a motor (not shown) into the lag tank, 13, containing water. In the lag tank about 2 /2 rolls or 1800 feet of the tubing were allowed to remain until drawn from the tank.

The rolls were mended by placing the lead end of a new roll onto finger, 17, the finger being about 10 inches long and having orifices, 18, through which a vacuum can be applied by connecting pipe, 19, to a vacuum source (not shown). The width of the finger need not be substantially greater than the width of the flattened tubing and is usually substantially equal to this width. In this embodiment, the width or diameter of the tubing and the width of the finger were about 53 millimeters. Vacuum was applied to hold the lead end firmly on the finger. The tail end of a previous roll was then taken, prior to its entry through the nip rolls 12, dipped into water, opened, and while dripping wet slipped over the vacuum finger 17 and the lead end of the new roll for a distance of 10 inches. The vacuum was then released and the mend (the connected ends) removed from the finger 17. After being drawn from the lag tank the tubing passed through squeeze rolls 14, over drip pan 15, through a mend detector unit 16, around a tension control spool 20, through a naphthol bath 21, over a bull-wheel 22 upon which printing occurred by the action of printing rolls 23 and 24. Ink was supplied to the printing rolls by the ink train composed of those rolls above the printing rolls which are collectively shown as 25 and 26. After passing through wash tanks 27 and 28 the printed tubing was wound on wind-up roll 29.

The process of this invention provided continuous printing of regenerated cellulose tubing at rates of 125 yards per minute, which is at least 25% greater than speeds of operation heretofore used. Furthermore, despite increased speeds, the process as described reduced rejected tubing by almost One source of rejected tubing was completely eliminated by this process. In the prior process, the operation was stopped while mends were made. Consequently, the tubing that was held up in the naphthol bath was olfshade and discarded. The present process is continuous, avoids hold-ups and eliminates this source of rejected tubing.

The most surprising feature of the invention is that it works. By merely wetting, then overlapping one end of gel regenerated cellulose tubing to be mended, the tubing having about the limpness of ordinary paper, over another end of gel regenerated cellulose tubing to be mended or inserting the latter end into the wetted end for a distance of at least about 10 inches, sufiicient friction is developed to withstand the tensions developed in this process. It was determined that these mends can withstand tensions as high as 4 pounds.

The invention is applicable to tubing having a diameter from 12 to 92 millimeters. It is also applicable to a continuous process operated below yards per minute, but is particularly advantageous for processes operated at 125 yards per minute and higher.

: h ang es and niodifieatious may be made without de- ;part-ing -from' the nature and "spirit of the invention.

' placing said-wet 'end aro'und'the other end o'f the tubing for a distance of at least about 10 inches.

2. ;A process 'for mending gel regenerated cellulose rtubin'g -which comprises flattening one end of gelregen- "eratedcellulose-tubing:and holding said end securely on'a flat surface, the width of-said surface being substantially equal to the width of said flattened endywett-ing thezoth'er 15 end with aqueous liquid and placing said wetted-end around the :fiattened end and said-flat surface for "a distauce of at least about 10 inches; and removing the ends 3. A process as in claim12 wherein the flattened end is held securely'by means of'vacuum applied through said flat surface. a

4. Arprocess as in claim, 2 wherein the overlap is 10 inches.

References 'Citedainfthe file of this patent UNITEDASTATES PATENTS 1238;635 Chandler .Au izs, 1917 2,183,691 Owens "Dec. 19,1939

o LFOREIGNPATENTS 743,229 Great Britain 4 Jan. 11, 71956 

1. A PROCESS FOR MENDING TWO ENDS OF GEL REGENERATED CELLUSLOSE TUBING WHICH COMPRISES WETTING ONE END OF THE GEL REGENERATED CELLULOSE TUBING WITH AQUEOUS LIQUID, AND PLACING SAID WET END AROUND THE OTHER END OF THE TUBING FOR A DISTANCE OF AT LEAST ABOUT 10 INCHES. 